Breech closure



United States Patent Claims. hi. 42-16) The invention relates to anautomatic firearm comprising a breech which is provided with asupplementary mass. Such supplementary masses are required in order toavoid troubles which are due to rebounding of the breech when runninginto its shooting position. In all known arrangements the supplementarymass consists of a movable piece mounted on the breech which exerts animpact either directly or over a spring onto the breech to prevent arebound of it. Since the elastic forces which effect the rebound of thebreech as well as the inert forces of the supplementary mass depend onthe speed of the breech, a satisfactory operation is guaranteed only fora rather small range of the firing rate. This is a considerabledisadvantage of the breeches provided with a supplementary mass.

The object of the invention is to avoid these defects of the knownsystems. According to the invention this is achieved in that thesupplementary mass is formed by a number of individual parts, which aremovable relative to one another under friction. Such a construction ofthe supplementary mass has the advantage that a damping of the movementof the supplementary mass which is high enough to prevent a rebound ofthe supplementary mass is obtained by the friction of the individualparts of the supplementary mass relative to one another and against thewalls of guiding means. By dividing the supplementary mass into manysmall individual parts the supplementary mass is losing its ownelasticity, so that the supplementary mass also for this reason has notendency to rebound and does not exert a very short and violent impactonto the breech but a lasting and effective thrust. Therefore a firearmaccording to the invention has a less critical breech speed so that withsuch an arm ammunition of different kinds can be fired, which can muchmore be adapted to predetermined requirements than up to now, since itis no more most important to observe a determined fire speed.

A further advantage of the invention is the extremely Simpleconstruction and a high reliability. This is especially true when,according to a further feature of the invention, the parts of the massare loosely filled into one or more chambers of the breech. In apreferred embodiment of the invention the breech is provided withaxially directed bores for lodging the parts of the mass and the boresare sealed preferably at their rear ends.

The parts of the mass are thereby formed by granules of a heavy metal,especially of tungsten. The use of granules of a heavy metal accordingto the invention has the advantage that such a granulated material has ahigh specific density and that the required supplementary mass can beaccommodated in a small space. Further the inner friction of such agranulated material is very high so that an excellent damping isobtained. Beyond that such a granulated material is also mechanicallyvery stable so that an abrasion does not occur.

Further objects, details and advantages of the invention are apparentfrom the following description in which the invention is explained indetail with reference to the embodiment shown in the drawing.

FIG. 1 shows a longitudinal section through a breech system with thebreech running into the shooting position, and

FIG. 2 shows a breech system according to FIG. 1 with the breech beinglocked.

The drawing shows .a breech system of known construction which has beenimproved according to the invention. The breech comprises a breech block1, a control member 2 connected therewith and a breech head 4 which ismounted on the control member 2 of the breech to be displaceable inaxial direction. The control member 2 has two control surfaces 3 whichcooperate with two interlocking rolls 5a and 5b which are disposed inopenings 6a and 6b of the breech head 4 and displaceable transversely tothe direction of the movement. When the breech is locked the rolls 5aand 5b enter the recesses 7a and 7b of an interlocking piece 7 in whichalso the barrel 8 is anchored. When the breech runs forward a cartridge9 is fed into the barrel 8 (FIG. 2). The cartridge can be fired by meansof the striker pin 11, which is displaceably disposed in the breechblock 1 and in the control member 2 and is normally kept in a restposition by means of a coil spring 10. For firing the cartridge 9 thestriker pin in known manner is knocked upon the bottom of the cartridgeby means of a cock (not shown).

According to the invention the breech block 1 of the breech comprisestwo axial bores 12a and 1217 which are filled almost to the half withheavy metal granules 13 serving as supplementary mass, preferably withgranules of tungsten. The rear ends of the bores 12a and 12b are sealedby means of screwed plugs 14a and 14b. The remaining hollow spaces 15aand 15b serve as working spaces for the supplementary mass 13.

As known after firing a shot the breech is moved opposite to thedirection of fire, whereby it cocks the propelling spring until it isbrought to rest by the thrust of the propelling spring or by the impactonto a buffer arrangement (not shown). The supplementary mass 13according to the invention which is in the front part of the bores 12aand 1212 when the breech is locked as shown in FIG. 2 due to its inertiais thrown back when the backward movement of the breech is deceleratedand rests against the plugs 14a and 14b as shown in FIG. 1. Due to itsinertia the supplementary mass remains in this position also during theforward motion of the breech which is effected by the forward motion ofthe breech which is eifected by the relaxing propelling spring (notshown). During the forward motion the breech head 4 removes a cartridgefrom a magazine or a belt in the usual manner and feeds it into thecartridge chamber in the barrel 8 of the arm.

After the breech head 4 has fed the cartridge 9 into the barrel of thearm and has come to rest the interlocking rolls 5a and 5b are pushedinto the recesses 7a and 7b by means of the control surface 3 of thefollowing control member 2. This proceeds under the development ofconsiderable forces resulting from the kinetic energy of the controlmember 2 and the breech block 1, which are both brought to rest. Theinterlocking piece 7 at first yields to the impact of parts 1 .and2 ofthe reech exerted over the interlocking rolls 5a and 5b, however it thenrebounds and presses the interlocking rolls 5a and 5b against thecontrol surfaces 3 of the control member 2, which in connection with theelasticity of the control member 2 would result in a rebound of breechparts 1 and 2 if no countermeasure were taken. In the moment of reboundthe individual parts of the supplementary mass 13 strike the frontsurface of the bores 12a and 1217, these parts are thrown forward fromtheir position near the plugs 14a and 1417 due to their inertia and thusexert a thrust onto the breech which acts against the forces which wouldcause a rebound of the breech. The impact of the granulatedsupplementary mass to the front surfaces of the bores 12a and 1212,however, does not, as in known breeches with a one-piece supplementarymass, take place as an elastic shock, which could again give rise torebound effects, which, however, should be avoided, but as anessentially inelastic shock, since the supplementary mass consisting ofindividual parts which are movable relative to one another has a highinner friction by which elastic vibrations of this mass are entirelyprevented. The inelastic impact of the supplementary mass effects alasting and effective counterthrust which definitely prevents a reboundof the breech and guarantees a perfect interlocking of the breech in avery extensive range of breech speeds.

It is to be understood that the invention is not limited to theembodiment described. The invention is quite independent from thespecific construction of the breech and can be applied on principle inall known breeches. Especially the supplementary mass according to theinvention may be used not only in a two-part breech as used in theembodiment described, but also in a one-part or mass breech. Furthermodifications of the specific embodiment described may be devised inthat certain of the features characterized by the claims may be used inother embodiments of the invention either individually or in anarbitrary combination. The elfect of the divided supplementary mass isnot only influenced by the total mass of the individual parts used butconsiderably also by the relation of their total volume to the volume ofthe chamber and beyond that also by the shape of the chamber in whichthe individual parts are assembled.

By the proper selection of these values the time slope and the value ofthe thrust of the supplementary mass can :be adapted to an optimum tothe given conditions.

What I claim is:

1. Automatic firearm comprising a breech provided with a supplementarymass, characterized in that said supplementary mass is formed by anumber of individual parts in mutual frictional contact, said partsbeing movable relative to one another.

2. Firearm according to claim 1, characterized in that the parts of thesupplementary mass are loosely disposed in one or more chambers of saidbreech.

3. Firearm according to claim 1, characterized in that said breech isprovided with axially directed bores for lodging said parts of saidsupplementary mass and that said bores are sealed preferably at theirrear ends.

4. Firearm according to claim 1, characterized in that the supplementarymass is formed by granules.

5. Firearm according to claim 4, characterized in that said granulesconsist of a heavy metal, especially of tungsten.

References Cited by the Examiner UNITED STATES PATENTS 2,495,460 1/1950Koucky 42l6

1. AUTOMATIC FIREARM COMPRISING A BREECH PROVIDED WITH A SUPPLEMENTARYMASS, CHARACTERIZED IN THAT SAID SUPPLEMENTARY MASS IS FORMED BY ANUMBER OF INDIVIDUAL PARTS IN MUTUAL FRICTIONAL CONTACT, SAID PARTSBEING MOVABLE RELATIVE TO ONE ANOTHER.